2ba64df2bc
wswrapper:
Getting the wswrapper.c LD_PRELOAD model working has turned out to
involve too many dark corners of the glibc/POSIX file descriptor
space. I realized that 95% of what I want can be accomplished by
adding a "wrap command" mode to wsproxy.
The code is still there for now, but consider it experimental at
best. Minor fix to dup2 and add dup and dup3 logging.
wsproxy Wrap Command:
In wsproxy wrap command mode, a command line is specified instead
of a target address and port. wsproxy then uses a much simpler
LD_PRELOAD library, rebind.so, to move intercept any bind() system
calls made by the program. If the bind() call is for the wsproxy
listen port number then the real bind() system call is issued for
an alternate (free high) port on loopback/localhost. wsproxy then
forwards from the listen address/port to the moved port.
The --wrap-mode argument takes three options that determine the
behavior of wsproxy when the wrapped command returns an exit code
(exit or daemonizing): ignore, exit, respawn.
For example, this runs vncserver on turns port 5901 into
a WebSockets port (rebind.so must be built first):
./utils/wsproxy.py --wrap-mode=ignore 5901 -- vncserver :1
The vncserver command backgrounds itself so the wrap mode is set
to "ignore" so that wsproxy keeps running even after it receives
an exit code from vncserver.
wstelnet:
To demonstrate the wrap command mode, I added WebSockets telnet
client.
For example, this runs telnetd (krb5-telnetd) on turns port 2023
into a WebSockets port (using "respawn" mode since telnetd exits
after each connection closes):
sudo ./utils/wsproxy.py --wrap-mode=respawn 2023 -- telnetd -debug 2023
Then the utils/wstelnet.html page can be used to connect to the
telnetd server on port 2023. The telnet client includes VT100.js
(from http://code.google.com/p/sshconsole) which handles the
terminal emulation and rendering.
rebind:
The rebind LD_PRELOAD library is used by wsproxy in wrap command
mode to intercept bind() system calls and move the port to
a different port on loopback/localhost. The rebind.so library can
be built by running make in the utils directory.
The rebind library can be used separately from wsproxy by setting
the REBIND_OLD_PORT and REBIND_NEW_PORT environment variables
prior to executing a command. For example:
export export REBIND_PORT_OLD="23"
export export REBIND_PORT_NEW="65023"
LD_PRELOAD=./rebind.so telnetd -debug 23
Alternately, the rebind script does the same thing:
rebind 23 65023 telnetd -debug 23
Other changes/notes:
- wsproxy no longer daemonizes by default. Remove -f/--foreground
option and add -D/--deamon option.
- When wsproxy is used to wrap a command in "respawn" mode, the
command will not be respawn more often than 3 times within 10
seconds.
- Move getKeysym routine out of Canvas object so that it can be called
directly.
109 lines
2.7 KiB
Bash
Executable File
109 lines
2.7 KiB
Bash
Executable File
#!/bin/bash
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usage() {
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if [ "$*" ]; then
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echo "$*"
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echo
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fi
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echo "Usage: ${NAME} [--listen PORT] [--vnc VNC_HOST:PORT] [--cert CERT]"
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echo
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echo "Starts the WebSockets proxy and a mini-webserver and "
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echo "provides a cut-and-paste URL to go to."
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echo
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echo " --listen PORT Port for proxy/webserver to listen on"
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echo " Default: 6080"
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echo " --vnc VNC_HOST:PORT VNC server host:port proxy target"
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echo " Default: localhost:5900"
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echo " --cert CERT Path to combined cert/key file"
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echo " Default: self.pem"
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exit 2
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}
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NAME="$(basename $0)"
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HERE="$(cd "$(dirname "$0")" && pwd)"
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PORT="6080"
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VNC_DEST="localhost:5900"
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CERT=""
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proxy_pid=""
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die() {
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echo "$*"
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exit 1
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}
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cleanup() {
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trap - TERM QUIT INT EXIT
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trap "true" CHLD # Ignore cleanup messages
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echo
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if [ -n "${proxy_pid}" ]; then
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echo "Terminating WebSockets proxy (${proxy_pid})"
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kill ${proxy_pid}
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fi
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}
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# Process Arguments
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# Arguments that only apply to chrooter itself
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while [ "$*" ]; do
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param=$1; shift; OPTARG=$1
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case $param in
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--listen) PORT="${OPTARG}"; shift ;;
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--vnc) VNC_DEST="${OPTARG}"; shift ;;
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--cert) CERT="${OPTARG}"; shift ;;
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-h|--help) usage ;;
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-*) usage "Unknown chrooter option: ${param}" ;;
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*) break ;;
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esac
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done
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# Sanity checks
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which netstat >/dev/null 2>&1 \
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|| die "Must have netstat installed"
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netstat -ltn | grep -qs "${PORT}.*LISTEN" \
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&& die "Port ${PORT} in use. Try --listen PORT"
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trap "cleanup" TERM QUIT INT EXIT
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# Find vnc.html
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if [ -e "$(pwd)/vnc.html" ]; then
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WEB=$(pwd)
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elif [ -e "${HERE}/../vnc.html" ]; then
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WEB=${HERE}/../
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elif [ -e "${HERE}/vnc.html" ]; then
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WEB=${HERE}
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else
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die "Could not find vnc.html"
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fi
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# Find self.pem
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if [ -n "${CERT}" ]; then
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if [ ! -e "${CERT}" ]; then
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die "Could not find ${CERT}"
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fi
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elif [ -e "$(pwd)/self.pem" ]; then
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CERT="$(pwd)/self.pem"
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elif [ -e "${HERE}/../self.pem" ]; then
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CERT="${HERE}/../self.pem"
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elif [ -e "${HERE}/self.pem" ]; then
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CERT="${HERE}/self.pem"
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else
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echo "Warning: could not find self.pem"
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fi
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echo "Starting webserver and WebSockets proxy on port ${PORT}"
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${HERE}/wsproxy.py --web ${WEB} ${CERT:+--cert ${CERT}} ${PORT} ${VNC_DEST} &
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proxy_pid="$!"
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sleep 1
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if ! ps -p ${proxy_pid} >/dev/null; then
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proxy_pid=
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echo "Failed to start WebSockets proxy"
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exit 1
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fi
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echo -e "\n\nNavigate to to this URL:\n"
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echo -e " http://$(hostname):${PORT}/vnc.html?host=$(hostname)&port=${PORT}\n"
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echo -e "Press Ctrl-C to exit\n\n"
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wait ${proxy_pid}
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